JPS61182301A - Fin line loading polarization coupler - Google Patents

Abstract

PURPOSE:To form a fin line loading polarization coupler with low reflection, low loss and excellent polarization coupler characteristic by constituting a sub waveguide with a waveguide having the same cross section as that of a main waveguide and providing a barrier having a thin and long hole for passing through a fin line gap to a joint between the main waveguide and the sub waveguide. CONSTITUTION:A polarized wave E1 incident from the left of the main waveguide 1 is transmitted along the fin line 6 while electric field is concentrated to the gap of the fin line provided in parallel with the direction of electric field, passes through a thin and long hole 9 and is branched into the sub waveguide 7. In this case, since the cross section of both the waveguides is made identical, the main waveguide impedance and the sub waveguide impedance for the polarized wave E1 are equivalent strictly or approximately, and the impedance change at the T branch joint between both the waveguides is less and the reflection due to impedance mismatching is almost neglected.

Description

[Detailed Description of the Invention] [Industrial Application Field] This emitting BA splits a % constant polarization from a multi-polarized main waveguide to a sub-waveguide. This invention relates to a polarization splitter that multiplexes a specific polarized wave propagating in a waveguide to a main waveguide that can share multiple polarizations.

[Conventional technology]

FIG. 3 is a diagram showing a conventional finline-loaded polarization splitter disclosed in, for example, Japanese Patent Application Laid-Open No. 50-122845. In FIG. 1, (1) is a square main waveguide capable of propagating two polarized waves;
2) is the rectangular sub-waveguide A that separates the polarized wave B1, +33 is the rectangular sub-waveguide B that separates the polarized wave E2, and +41 is the rectangular sub-waveguide B that separates the polarized wave Fil from the square main waveguide (1). Waveguide A (2
), (5) is the fin line B that leads the polarized wave E2 from the square waveguide (1) to the square sub-waveguide B (3).

A conventional finline-loaded polarization splitter is constructed as described above, with two orthogonal side waves E1 and B coexisting in the main waveguide.
2 is transmitted along the fin line and fin line B while concentrating the electric field in the gap between the fin lines installed parallel to each polarization direction, and is split into each sub-waveguide branch port. do.

[Problem that the invention seeks to solve]

With a conventional finline-loaded polarization splitter like the one above,
Broadband demultiplexing is possible due to the finline beam effect, but at the T-branch junction between the main waveguide and sub-waveguide, the difference in cross-sectional shape of the waveguides makes it difficult to use the ridge waveguide as a ridge waveguide. There has been a problem in that impedance mismatch occurs, resulting in non-negligible deterioration of reflection characteristics. Furthermore, if the fin line gap is made smaller to increase the degree of electric field concentration in order to reduce this impedance mismatch, there are problems such as an increase in transmission loss resulting in high loss.

The present invention was made to solve these problems, and its object is to obtain a broadband finline-loaded polarization splitter with low reflection and low loss.

[Failure to solve the problem]

The finline-loaded polarization splitter of the present invention comprises a sub-waveguide having the same cross-section as the main waveguide, and further includes a partition wall and a partition wall at the junction between the main waveguide and the sub-waveguide. The partition wall of the lever is provided with a pore that passes through the gap between the fin lines.

[Effect]

In this invention, since the auxiliary waveguide and the main waveguide are constituted by waveguides having the same cross section, the impedance of each waveguide is strictly or approximately equal.

It reduces the impedance mismatch near the T-branch coupling and reduces the reflection of radio waves.At the same time, it can reduce the electric field concentration of polarized waves along the fin line, so the fin line gap can be widened. Enables low-loss transmission.

Moreover, the partition wall has a pore passing through the fin line gap provided at the junction of the main waveguide and the sub waveguide.

It suppresses the coupling of radio waves of different polarization to the polarized waves branched to the sub-waveguide, and has the effect of increasing the degree of separation of polarized waves.

〔Example〕

FIG. 1 is a partially sectional view showing an embodiment of the present invention.
(1) is the same as the conventional finline-loaded polarization splitter described above. (6) is a fin line, (7) is a sub-waveguide with the same cross section as the main waveguide (1), and (8) is provided at the junction of the main waveguide (1) and sub-waveguide ()). bulkhead, (9)
is a pore passing through the fin line gap provided in the partition wall (8).

Figure 2 is a cross-sectional view showing the internal outline of the fin line loaded polarization splitter shown in Figure 1 above, and the valley components are the same as in Figure 1 ◎ The fin line loaded polarization splitter configured as above In the device, the polarized ml incident from the left side of the main waveguide (1) in Figure 1
h is the fin line (6
), the electric field is concentrated in the gap and transmitted along the fin line,
The light passes through the pore (9) and is split into the sub waveguide (7). At this time, the main waveguide impedance and the sub waveguide impedance for the polarized wave E1 are strictly or approximately equivalent since the cross sections of both waveguides are selected to be the same, and both waveguides are joined. There is little impedance change at the T-branch coupling, and reflections due to impedance mismatch can be almost ignored.

Moreover, as mentioned above, with the elimination of the impedance mismatch of the finline-loaded waveguide, there is generally no need to reduce the finline gap to reduce the impedance mismatch by increasing electric field concentration on the finline. On the contrary, this gap can be made wide and the transmission loss of the polarized wave E1 can be reduced.

On the other hand, polarization Il! 2 is the fin line (6) in the main wave tube
Since the direction of the electric field is perpendicular to the fin line, the electric field is not affected by the fin line and is transmitted as it is to the right in Figure 1 within the main wave tube with almost negligible reflection and transmission loss. A partition wall (8
) is the polarization l! +2 sub-waveguide (71l! This suppresses the intrusion into the I, and at the same time suppresses the impedance change at the T-branch coupling between the main waveguide and the sub-waveguide for polarized wave 1!!2. In addition to increasing the degree of polarization separation as a polarization splitter for two polarizations E1 and m2, polarization FX2
It has the effect of reducing reflection.

Incidentally, in the above embodiment, the wave splitting theory was explained using one sub-waveguide, but the operation and effect are the same even when a large number of sub-waveguides are coupled to the main waveguide. Furthermore, the same effect can be achieved even if the main waveguide is a circular waveguide that can be used for multiple polarizations. [Effects of the Invention] As explained above, the present invention is capable of using a sub-waveguide as a waveguide with the same cross section as the main waveguide. In addition, by providing a partition wall with a pore for passing through the fin line gap at the junction between the main waveguide and the sub-waveguide, the T-branch junction between the main waveguide and the sub-waveguide is By suppressing impedance changes and allowing the finline gap to spread widely, a finline-loaded polarization splitter with low reflection, low loss, and excellent polarization separation characteristics is achieved.

[Brief explanation of drawings]

FIG. 1 is a partially sectional view showing an embodiment of the present invention. FIG. 2 is a sectional view showing an internal outline of an embodiment of the present invention;
FIG. 3 is a partial cross-sectional view showing a conventional finline-loaded polarization splitter. In the figure, (1) is the main waveguide, (2) is the rectangular sub-waveguide A, +31 is the rectangular sub-waveguide B, (4+ is the fin line A. (5) Huff in line B, f61 is the fin line, (7
) is a sub-waveguide, (8) is a partition wall, and (9) is a pore.The same reference numerals in each figure indicate the same or equivalent parts. 11111m 6: Rai〉rai〉 7: Starry 4i skin tube! 21st! ! E.

Claims (1)

[Claims] A main wave pipe that propagates radio waves polarized in multiple directions different from each other, and a main wave pipe that is installed in a direction perpendicular to the main wave pipe and that propagates radio waves polarized in a specific direction among the radio waves that propagate through the main wave pipe. Polarization consisting of one or more sub-waveguides that separate radio waves, and a fin line that guides the radio waves polarized in the specific direction from the main waveguide to the sub-waveguide. In the wave device, the sub-waveguide is configured with a waveguide having the same cross section as the main waveguide, a partition is provided at the junction of the sub-waveguide and the main waveguide, and the partition is further provided with a partition wall. A finline-loaded polarization splitter characterized in that a fine hole passing through the gap between the finlines is provided.